The present disclosure finds its genesis in a theatrical illusion which is widely known as “Pepper's ghost”. In this illusion, a viewer is made to believe that he is seeing an article which does not, in fact, exist in the setting or circumstances being viewed. The techniques involved in presenting Pepper's ghost are described hereafter. However, for now, a brief description and history of Pepper's ghost is provided.
In order for the classical Pepper's ghost illusion to work properly, the viewer must see clearly into a main setting, but not see into a hidden room. Unknown to the viewer, the viewer is also viewing the main setting through an angled piece of glass which, because of its placement, may be both translucent and reflective. By changing the lighting in the hidden room, the viewer may view a reflection of the lit contents of the hidden room, on the glass panel. Thus, the illusion is controlled by its illumination, and will appear and disappear when the lighting of the object, person, or the like, is turned on or off, respectively. As a result, an object or person which is reflected in the “mirror” section of the glass (e.g. the reflective surface of the glass) may seem to appear or disappear, or change into another object. While this illusion is over 100 years old, the same effect has been employed since at least the 1960's in certain modern theme parks, where objects such as reflected animated props may create the appearance of translucent “ghosts” which appear to be moving through a particular setting and interacting with props in that physical particular setting. Moreover, the images appear to be three dimensional and demonstrate a parallax effect with respect to other items on the stage.
Typically, in recent applications, a polymeric film, drawn tight within a metal frame, is used to replace the glass panel, and a projection device is used to create the image to be displayed on the polymeric film. Construction of the film and associated frame, and the projectors to be used, are well known in the art, and outside of the scope of the present invention.
As an example, U.S. Pat. No. 8,172,400 (O'Connell et al.) describes a projection apparatus which requires a first projection device that is arranged to generate a virtual three dimensional object by projection of the image onto to a reflected/translucent polymer film. A second projection device projects a background image; and a light source projects light onto the virtual three dimensional image. A stage arrangement may also be provided, which is placed behind the screen, upon which a presenter or actor, or a prop, or both, may be located, in order that the presenter or prop, interact with the virtual image.
In more recent applications, such as those described in US Patent publication No. US 2013/0300728 (Reichow et al.), the polymeric film or glass panel showing the reflection is replaced by a transparent front display device, such as an transparent LCD display device. In this approach, the reflective surface with its projected image, is no longer required since the virtual image may be displayed directly on the transparent front display. A background display device is positioned visually behind the transparent front display, and a background image is shown or projected directly on the background display device. The images shown on the background display device may be coordinated with the images on the transparent front display in order to create an apparent parallax effect which provides images which are similar to images from the Pepper's Ghost technique.
Additional display panels may be provided between the front display and the background display, in order to provide additional image content. However, for simplicity, the use of a two panel approach will be discussed in the present document.
Current uses of this simulated 3D presentation technique may include, for example, the display of advertising materials in a simulated 3D environment, or the simultaneous presentation of a speech to numerous groups in many different locations, using a virtual image. Other applications have included providing a virtual performance by a performer, even though, in some cases, the performer is no longer alive.
However, unless a visual “ghost” effect is desired, it has typically been necessary to employ a black background surface behind the virtual image so as to avoid any background image showing through the virtual image. This is because if the viewer were to see the background image through the front image, it would destroy the “holographic” effect of the virtual image.
More recently however, the background image is adjusted so as to be coordinated with the transparent front image so that the two images are mated one to the other. As an example, a blacked-off “masked” area may be provided on the background display which masked image moves and/or is otherwise coordinated with the image on transparent front display so as to minimize or eliminate the background image from bleeding through the image on the front display.
In order to provide a simulated 3D effect using a front panel and a background panel (or any additional intermediate display panels), it is necessary to provide at least some distance between the transparent front display and the background display. This distance typically varies depending on the size of the display, and is used to create the parallax effect.
A common problem with this approach is that the light from the background panel is used to provide the lighting effect on the front panel. As such, with normal background panels and projection apparatuses, the combined 3D image is dark and/or dull, and is typically only useful in darkened display areas. While this is acceptable in some display areas, it is not practical for use in well-lit areas, such as in outdoor displays, or displays in a mall setting.
To address this issue, the prior art displays may be enclosed in a box so as to minimize the amount of ambient light that falls on the screen. However, these boxes require a relatively large profile, which increases the overall size of the screen, and thereby, limit their use in commercial applications. Also, because of the darkened box approach, typically only those standing directly in front of the box display may see the images on the screen. Thus, the ability to show the images to a larger group of people is limited.
A further problem with prior art display systems is the creation of an undesirable visual effect, call moire, wherein false patterns are observed in the final image, as a result of interaction between the visual display lines from the images on the front and background panels. These typically appear as a pattern of roughly parallel lines, or the like. This leads to unacceptable image quality, and is particularly prevalent in systems having lower image quality, or low resolution, display systems. Using higher resolution screens may therefore be expected to reduced the amount of moire observed in the combined image, however, this leads to an increased cost for the simulated 3D screen apparatus.
As such, it would be beneficial to provide a simulated 3D display device of the type described herein, wherein the screen apparatus is capable of being used in higher lighting situations. Furthermore, it would be beneficial to also provide a simulated 3D display device, having a low profile. Still further, it would be beneficial to also provide a simulated 3D display device which has been modified to reduce and/or ameliorate the moire effect, observed in other simulated 3D projection devices.
The present inventors have unexpectedly discovered that the at least some of these benefits may be provided in a novel, low profile simulated 3D display device, which may be viewed simultaneously by a plurality of viewers, in normal ambient lighting conditions.